1. Field of the Invention
The present invention relates to an image sensing apparatus using optical coherence tomography utilized in ophthalmic care, and the like, and also to a method of controlling the image sensing apparatus.
2. Description of the Related Art
Currently, various pieces of optical equipment have been used as ophthalmic equipment. Of those, as optical equipment observing eyes, various pieces of equipment such as an anterior segment photographing machine, a fundus camera, a scanning laser ophthalmoscope (SLO), and an image sensing apparatus (hereinafter, referred to as “OCT apparatus”) using optical coherence tomography (OCT) have been used. Of those, the OCT apparatus takes a tomographic image of a fundus with high resolution.
The OCT apparatus irradiates a sample typified by a retina with low coherent light and measures reflected light from the sample with high sensitivity, using an interferometer. Further, the OCT apparatus scans the sample with the low coherent light and allows the reflected return light and reference light from the same light source, which has passed through a reference optical path, to interfere with each other, to thereby take a tomographic image. Such an OCT apparatus has been widely used in ophthalmic diagnosis particularly for taking a tomographic image of a retina.
The OCT apparatus takes a tomogram, and hence, may only take an image of one cross-section at a certain timing with a single interferometer configuration. Therefore, it is difficult to take a tomographic image in a cross-section passing through a disease site exactly. In order to solve this problem, according to the technology disclosed by Japanese Patent Application Laid-Open No. 2008-029467, an example is illustrated in which an OCT tomographic image (B-scan image) and an SLO image are displayed on the same screen, and in which an appropriate B-scan tomographic position is shown. However, there still remain problems that an image showing a disease is not always shown on the SLO image, and that needs for taking tomograms of a disease site with a plurality of OCT tomographic images may not be satisfied.